Postharvest Technology - Assignment 3 - Cc01 - Group 06.Pdf

POSTHARVEST TECHNOLOGY ASSIGNMENT 3 CC01 GROUP 06 LITCHI Proposing post harvest treatment of To distribute to domestic supermarkets Members GROUP 4 Lê Yến Nhi 2053302 Phạm Nhật Quyên 2053387 Trần Than[.]

Proposing post harvest treatment of

To distribute to domestic supermarkets

GROUP 4

Lê Yến Nhi - 2053302 Phạm Nhật Quyên - 2053387 Trần Thanh Minh -1852585

Đỗ Hoàng Phúc - 2052653

Trần Thị Ngọc Huyền - 2053058

3 Postharvest diseases and common pathogens

4 Proposed postharvest treatments

5 Packaging method

Vietnam is one of the largest litchi exporters in the world, with many varieties growing and bringing

significant econimic value During production and processing, the steps for harvesting and preserving fruit are important to ensure quality of the fruit and can have a direct

impact on consumers

1.THE DIFFERENT MATURITY INDICES OF THE PRODUCT

Lichi is a non-climacteric fruit and therefore it is advantageous to pick fruit soon after it reaches maturity This also ensures that fruit has the maximum shelf life

Litchi harvesting is always a delicate task

Level of acidity will drop significantly and the fruit may become rather tasteless

Following criteria may be followed to ascertain the litchi maturity:

PHYSICAL METHODS:

Skin colour is usually a determinant of ripeness The

fruit is said to be ready for harvesting when the pericarp is a uniform red, (just when the orange colour has disappeared completely or almost completely, except in the case of cultivars which produce yellow

or green fruit) and the protuberances have become smoother

In varieties which produce red fruit, these should be

an even deeper red at harvest time.

PHYSICAL METHODS:

Figure 1 Growth and development of litchi fruit from 2 weeks after anthesis (Source: L V Trong et al., 2021, Physiological changes during the growth and development of litchi fruit (Litchi

chinensis Sonn.) grown in Vietnam, Rev Bras Frutic, Jaboticabal, v 43, n 2)

Fruit size: minimum of

25 mm in diameter

PHYSICAL METHODS:

Chemical methods:

Testing is another way of determining whether the fruits are ready for picking

As litchi fruit mature, the concentrations of sugars, principally those of sucrose,glucose and fructose increase, while the concentrations of organic acids,

predominantly malic acid decrease

PHYSICAL METHODS:

Table 1 Content of reducing sugar, starch, total organic acid, vitamin C in litchi fruit

(Source: L V Trong et al., 2021, Physiological changes during the growth and development of litchi fruit (Litchi chinensis

Sonn.) grown in Vietnam, Rev Bras Frutic, Jaboticabal, v 43, n 2)

Chemical methods:

In the fruit period from 8 to 10 weeks, the content of reducing sugar increased rapidly and reached 14.237% when the fruit was at 10 weeks The total organic acid content decreased at 10 weeks due to organic acid used in respiration to

provide energy for starch synthesis processes.

PHYSICAL METHODS:

Chemical methods:

Another useful test of ripeness is to check the colour of the inner surface of the

skin, which should also be red Class of surface redness is the prime method to

judge the fruit maturity The youngest fruit (<33 per cent red) and the oldest fruit(100 percent red) have lower aril concentrations of total soluble solids and higherpericarp superoxide dismutase activity than intermediate fruit The youngest fruitalso has higher rates of water loss than older fruit

2.RESPIRATION RATE

RESPIRATION RATE OF LITCHI:

Litchi fruit are non-climacteric with no significant respiration peak after harvest

The respiration rate declined at the early stage of storage but increased after thepericarp being turned brown

After the fruit was transferred out from the cold storage, the temperature of fruitincreased, resulting in a gradual browning of pericarp

RESPIRATION RATE OF LITCHI:

The respiration rate was high, releasing CO2 up to 200 mg/kg.hr at roomtemperature and to 60-80 mg/kg.hr in cold storage The high respiration rate mayresult in rapid consumption of nutrients, leading to a loss of taste after storage

The respiration rate of fruit stored at room temperature was three times higher thanthat in cold storage

During the course of storage at low temperature, the respiration of litchi fruitdeclined and became very weak after 40 days of storage

Classification of low and high respiration rate of litchi:

RESPIRATION RATE OF LITCHI:

As a non-climacteric fruit, litchi has low production of ethylene

The exogenous ethylene inhibitor (STS) inhibited ethylene production in the fruit,retarded the growth, and resulted in negative effects such as delaying andworsening the color of fruit and excessive fruit-drop and cracking

In normally matured fruit, the amount of ethylene released was less than that inover-ripe fruit

When litchi fruit were stored at room temperature for 3-5 days, the amount ofethylene released had a considerable increase and then decreased slightly

The sensitivity of ethylene:

RESPIRATION RATE OF LITCHI:

The lower the temperature, the less amount of ethylene released

In the course of storing at 5℃ and 8℃, ethylene production increased gradually,while at 1℃, it remained at a lower level throughout

When fruit were transferred to 20℃ from cold storage, ethylene and ACC bothshowed an increase at 5℃ and 8℃, whereas fruit stored at 1℃, the amount ofethylene released remained at a lower level and ACC decreased

When fruit were transferred to room temperature after storing at low temperature,the ethylene production increased rapidly and reached a peak at 14 hr before itdecreased

The sensitivity of ethylene:

3 POSTHARVEST DISEASES AND

COMMON PATHOGENS

POSTHARVEST DISEASES AND COMMON PATHOGENS

The infection reduces production and shelf life

Flower panicles are particularly susceptible

Browning of flowers and desiccation of panicles, attacking young andripe fruits causing brown lesions and white downy growth or prematurefruit drop are the symptoms

Immature fruit turn brown, while those infected before harvest have awhite mildew growing on the skin

Downy blossom blight of litchi: Caused by Peronophythora litchi It

attacks both young and ripe fruit, pedicels and leaves of litchi

Figure 2 Lychee (Litchi chinensis) fruits: healthy (left) and affected by Peronophythora litchii (right)

POSTHARVEST DISEASES AND COMMON PATHOGENS

The pathogen probably persists as zoospores or dormant mycelium in the soil or inplant debris

Higher temperatures during the day are suitable for sporulation, germination andinfection by the pathogen, and lower temperatures and high humidity at nightfacilitate zoospore release and distribution

Continuous rain and re-infection are the most important factors leading to the widedistribution of this disease

The spots usually start from the tip or the margin of thelamina These spots are deep chocolate in colour.

Anthracnose (Colletotrichum gloeosporoides), attacks

leaves and branches, along with flowers and flower stalks,and fruit

Outbreaks are common after warm wet weather Theinfection remains restricted to lower surface During therainy season, the rain water trickling through the diseasedleaves is richly laden with the spores of the pathogens tocause further infections

Anthracnose: caused by B theobromae

POSTHARVEST DISEASES AND COMMON PATHOGENS

Tree Decline and Root Rot: A slow decline and a sudden death have been recorded

in litchi It can affect the whole tree or just one or two branches The symptomsinclude a sudden branch wilt that is followed by the decline of new growth on theaffected branch over a period

POSTHARVEST DISEASES AND COMMON PATHOGENS

In some parts of the litchi belt, trees are killed by the root rot Some isolated cases

of root collar rot caused by Botryodiploidia theobromae This can quickly kill the

trees and no satisfactory control method has been established

A species of Fusarium has been isolated which is associated with the sudden death

of the plant One side of the tree’s crown may be perfectly sound and the othertotally necrosed Leaf shed never occurs (it does in the case of a nematode attack)and the internal parts of the roots are characteristically red in colour

As with the previously mentioned cases, no control method has been reported Nomethod has been found to save the tree once it has become infected

POSTHARVEST DISEASES AND COMMON PATHOGENS

The alga starts its appearance as small dark isolatedpatches which spread very fast and ultimately developinto a velvet reddish brown to orange colouredcushion like growth

Algal filaments associated with both asexual andsexual reproductive organs, grown on both thesurfaces of leaves and penetrate deep between cuticleand epidermis and sometimes extend betweenadjacent epidermal cells into the layer of parenchymabelow epidermis

Red Rust: It is a parasitic algae, which occasionally

attacks trees causing loss of vigour

POSTHARVEST DISEASES AND COMMON PATHOGENS

4 PROPOSED POSTHARVEST

TREATMENTS

Litchi fruit sales make a significant contribution to economic development inthese countries, especially those in South-East Asia

Most litchi fruit produced in Asia are marketed locally, with some regionalexports to Hong Kong, Malaysia and Singapore, and fewer exports to moredistant centers in Europe and the Arab States

In contrast, litchi production has a strong export focus in Israel, South Africaand Thailand

PROPOSED POSTHARVEST TREATMENTS

Litchi fruit have a short storage life under ambient conditions and, asexportation can take 1–2 weeks from producer to consumer, this inherentlimitation can impede trade

The major disorders affecting litchi fruit appearance are pericarp browning andpathological decay

Postharvest technologies which have been developed to reduce these disordersinclude heating and cooling the fruit, the use of various packages andpackaging materials and the application of fungicides and other ameliorativechemicals Thus, most published postharvest research has focused on reducingthese 2 disorders and on disinfestation to produce highly coloured fruit, free ofdisease and insects

PROPOSED POSTHARVEST TREATMENTS

Research on postharvest biology and technology for litchi fruit continues at arapid pace This overview considers the current status of postharvest research

in litchi fruit, particularly since 2003 (Jiang et al 2003), with an emphasis onpostharvest technology

PROPOSED POSTHARVEST TREATMENTS

Postharvest techniques that have been

investigated to maintain quality of harvested

litchi fruit include sulfur fumigation,

fungicide dipping, waxing, chitosan coating,

microbial antagonists, irradiation and heat

treatments Sulfur and fungicide treatments

have been adopted commercially, whereas

the other approaches require further

development

Sulfur fumigation: was once considered the most effective and practicaltreatment to reduce browning in litchis Sulfur dioxide inhibits non-enzymaticformation of colourless quinone-sulfite complexes and enzymatic browning byinactivation of PPO

Acid dips: Fading of the bright red litchi fruit skin during storage is probablydue to an increase in cell sap pH

Oxalic acid: due to inhibition of degradation and oxidation of anthocyaninsand also to the maintenance of relatively low peroxidase activity Thecommercial use of oxalic acid merits further evaluation

Treatments to maintain skin colour :

PROPOSED POSTHARVEST TREATMENTS

5 PACKAGING METHOD

Wooden boxes are popularly used to pack litchi by growers and distributersdue to the physical strength they offer

Wooden containers of 18-22 kg capacity are still being commonly used in theform of reusable boxes or crates

Wooden box packaging:

PACKAGING METHOD

They not only offer the benefits ofstrength and reusability, woodenboxes when made to a standard sizestack well on trucks or storagerooms

They are not environment friendly as their usage leads to felling of trees.

Obtaining uniformity of weight is a problemThey are heavy and costly to transport

They may cause compression and vibration injuries if contents are over- orunder-packed

They often have sharp edges, splinters, and nails etc, which can easily causedamage to contents These leads to the excess moisture loss from the litchifruits Litchi moisture loss has been shown to result in increased conductivity

of pericarp tissues and loss of membrane integrity

Wooden box packaging:

The disadvantages of wooden containers are:

PACKAGING METHOD

As these crates are strong and rigid they can be used for many journeys,making the cost per journey relatively low

Reduce the storage space requirement and transport cost of empty containersLess mechanical damage to fruits during transportation and handling

Different sizes and shapes are availableThey can be easily cleaned and disinfectedThey are strong and weather resistant and because of this they can be used inhumid areas

Plastic crates:

The advantages of plastic crates are:

PACKAGING METHOD

Plastic crates are usually made of highdensity polyethylene (HDPE) or PP byinjection molding

Polyethylene has higher impact strengthand a low degradation by ultra-violetradiation while polypropylene has abetter scratch resistance

The performance of both materials can

be improved by adding antioxidants and

UV protectants

Plastic crates:

PACKAGING METHOD

Cardboard boxes are available in a wide range of sizes, designs, and strength

It is light and clean, and can readily and easily be printed upon with nutritionalinformation, weight, amount, etc Because of its relatively low cost andversatility CFB boxes remain the dominant package container for litchi

CFB boxes were very effective in significantly reducing mechanical andpathological losses, whereas browning and fresh weight loss (FWL) wasreduced by about 50%

Cardboard (fibreboard) packaging:PACKAGING METHOD

Most CFB boxes are made of three or more layers ofpaperboard manufactured by the Kraft process Theyare nowadays laminated to protect from exposure tomoisture but still easily damaged by careless handlingand stacking

Different types of flexible plastic films like LDPE (LowDensity Polyethylene), PVC (Poly Vinyl Chloride), PP(Polypropylene) and cellulose acetate films are used forpackaging of horticultural produce

These films are mostly used as pouches with holespunched at regular intervals to allow respiration Theyare available in a wide range of thicknesses and gradesand can be engineered to control the environmentalgases inside the pouch LDPE is the most widely usedmaterial Plastic bags reduce moisture loss from storedfruit over a broad temperature range

Poly bag packaging:

PACKAGING METHOD

In Asian countries such as China andThailand, litchis are usually packed intopolyethylene bag (0.02-0.05 mm thick)and placed in polystyrene boxes while ice

is placed on top of the sealed bag.Packaging materials coupled with coldconditions increased the shelf life of litchi

to 16 days

Poly bag packaging:

PACKAGING METHOD